<!DOCTYPE html>
<html lang="en">
<head>
</head>
<body>
<script>
    var a = 3;
    function test(a) {
        console.log(a)
    }
    function test2() {
//        'use strict';
        let a = 1;
        return test(a);//1
    }
    test2();//1
</script>
</body>
</html>